<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, initial-scale=1.0">
		<title></title>
		<link rel="stylesheet" href="./Bootstrap4.6.1/css/bootstrap.css">
		<script src="./Bootstrap4.6.1/js/jquery.js"></script>
		<script src="./Bootstrap4.6.1/js/bootstrap.bundle.js"></script>
		<style>
			div{
				width: 100px;
				height: 100px;
				/* margin: 30px; */
				/* background-color: red; */
			}
			.div5{
				border: 1px solid;
			}
			/* bootstrap全局样式可用可不要,也可以和原生css混用 */
		</style>
	</head>
	<body>
		<a href="" class="text-danger">连接</a>
		<div class="border text-white bg-dark m-5">div1</div>
		<div class="border-top border-primary bg-success text-white p-5">div2</div>
		<div class="border-bottom border-success ml-5">div3</div>
		<div class="border border-left-0">div4</div>
		<div class="border-primary div5">div5</div>
		<div class="rounded">圆角01</div>
		<div class="rounded-left">圆角02</div>
		<div>圆角03</div>
		<p class="w-75">
			<span class="w-75">负外边距</span>
		</p>
	</body>
</html>